The manufacture of organic electronic devices may be performed using solution deposition techniques. One process for making organic electronic devices is to deposit organic material layers on a substrate by ink jet printing. In an ink jet process, the liquid composition of the ink drops includes an organic material in a solution, dispersion, emulsion, or suspension with an organic solvent or with an aqueous solvent. After deposition, the solvent is evaporated and the organic material remains to form an active layer for the organic electronic device.
Forming high-resolution patterns, e.g., 200 dpi (dots per inch) with ink jet printing technology requires that each droplet be relatively small. Typically, for a device with 100 to 130 dpi, the droplet volume ranges between a few tenths of a pico-liter to a few pico-liters. When the volume of the droplet is in this range, fluctuations of the volume among different droplets become significant, as the volume stability must be controlled. In addition, because of the small volume and mass of each droplet, control of the delivery to pre-defined locations becomes a factor, as the fluctuation of spatial accuracy may occur due to process limitations, e.g., substrate or printhead movement, or delivery system.
There remains a need for an electronic device with high resolution.